气固同轴射流流场特性PIV实验与CFD模拟

PIV Experimental and CFD Simulation of Gas-Solid Coaxial Jet Flow Field Characteristics

以粒子图像流场测量(PIV)与计算流体力学(CFD)数值模拟相结合的方法,对气相和气固两相同轴射流流场特性进行了研究,探究了射流速度比、喷嘴直径、射流空间直径和射流出口直径对回流量和回流区域的影响规律。结果表明:射流区和壁面之间存在沿轴向延伸至整个射流长度的回流区域,中等Stokes数颗粒会随回流气体改变运动轨迹,聚集在低涡量高应变的回流涡点;射流速度比、喷嘴直径和射流空间直径对回流量影响显著,实验工况下的最大回流量是射流量的10.29倍;当射流充分发展后,射流出口直径对回流量没有影响。通过气固两相同轴射流流场特性的研究,为进一步阐明气固耦合的颗粒弥散机理提供了理论指导。

The flow field characteristics of gas phase and gas-solid two-phase coaxial jets were studied by particle image velocimetry (PIV) flow field measurement and computational fluid dynamics (CFD) numerical simulation. The effects of jet velocity ratio,nozzle diameter,jet space diameter and jet outlet diameter on recirculation flow and recirculation zone were explored. The results showed that there was a recirculation flow regime extending along the axis to the whole length of the jet between jet zone and confined wall. The particles of moderate Stokes numbers and turbulent coaxial jets changed the trajectories with the recirculating air and enrichment at the return vortex points with low vorticity and high strain. The jet velocity ratio,nozzle diameter and jet space diameter had a significant influence on the recirculation flow. The maximum recirculation flow under experimental conditions was 10.29 times larger than the jet flow. When the jet was fully developed,the exit jet diameter had no effect on the recirculation flow. Through the study of the characteristics of gas-solid two-phase coaxial jets flow fields,it provided theoretical guidance for further clarifying the particle dispersion mechanism of gas-solid two-phase coupling.